Optical reading apparatus

ABSTRACT

An automatic optical reading apparatus ( 1 ) having a light emitting section ( 26 ), a light receiving section ( 27 ) and an outside interface section ( 36 ). A first unit ( 2 ) houses at least one of the emitting section ( 26 ) and the receiving section ( 27 ) and a second unit ( 3 ) houses at least the outside interface section ( 36 ). The first unit ( 2 ) and the second unit ( 3 ) are mutually connectable in at least two different mutual orientations.

RELATED APPLICATIONS

This application claims priority to European Application No. 01830631.6filed Oct. 5, 2001 and U.S. application Ser. No. 10/167,991 filed Jun.10, 2002, now U.S. Pat. No. 7,197,162 issued on Mar. 27, 2007.

TECHNICAL FIELD

The present invention relates to an optical reading apparatus, and,preferably to an automatic optical reading apparatus.

BACKGROUND OF THE INVENTION

In general, an optical reading apparatus comprises:

a light emitting section, comprising at least one light source—forexample one or more LEDs or a laser light source—, optional opticalshaping and/or focusing components for the light emitted by the lightsource, and optional means for scanning the light emitted by the lightsource, for example one or more rotating or oscillating mirror surfaces,and

a light receiving section comprising at least one photosensitiveelement, for example one or more photodiodes or a CCD or C-MOS device,generating an electrical signal having an amplitude proportional to thelight incident on it, and optional optical

The optional shaping and/or focusing components of the emitting sectionand the optical collecting and/or focusing components of the receivingsection can partly or totally coincide. The casing of an optical readingapparatus thus comprises an emitting window, a receiving window, or anemitting/receiving window.

An optical reading apparatus generally comprises also devices forprocessing the output signal of the photosensitive element or elementsof the receiving section, such as an amplifier, an analogue-to-digitalconverter, or a sampler.

In the particular case of bar code or two-dimensional two-color—commonlyblack and white—code readers, moreover, a digitizer can be comprised, inaddition to or as an alternative to the analogue-to-digital converter orto the sampler.

Moreover, an optical reading apparatus can comprise a microprocessorprocessing unit. In the case of an optical code reader such a processingunit, commonly indicated as a “decoder”, is intended to decode theoptical code being read, including the optional reconstruction of theoptical code from partial scan lines. In the case of other opticalreading apparatuses, such a processing unit is intended to perform thespecific function of the optical reading apparatus, for example todetermine measures of distances and volume of objects, to detect theirpresence, etcetera.

The expression “automatic” is used as opposed to the “portable” or“manual” terms, that is to say, to indicate an optical reading apparatusto be used without human actuation. Such apparatuses, also known as“unattended scanners”, are used, for example, at a conveyor belt (orother handling means) on which items to be detected travel, or at afixed station where an operator manually enters the items to bedetected, or also on machinery moving the optical reader, such as forexample on a forklift in a store. Item detection can comprise thereading of an optical code and/or the measurement of a distance and/orof a volume, etcetera.

An automatic optical reading apparatus generally is part of a complexsystem, wherein it interacts with other optical reading apparatuses,other electro-optical devices such as height sensors, other electrical,electromechanical and/or electronic devices, in particular for dataprocessing.

More in particular, the output signal of the photosensitive element ofthe receiving section, optionally treated and/or processed by theabove-mentioned additional components, can be transmitted outside theoptical reading apparatus to an external processing unit for furtherprocessing. Moreover, the information content detected by the opticalreader (the particular code read, the determined distance or volume, anON/OFF signal, etcetera) is typically transmitted outwards, for examplein a control unit of an automatic item sorting system, in the managementof a store, in an automatic machinery, a cash register, etcetera.

Moreover, besides the necessary power supply, an optical readingapparatus typically receives one or more input control signals. Forexample, in a system for detecting items travelling on a conveyor belt,besides one or more optical code readers oriented so as to read anoptical code wherever arranged on the surface of an item and an optionaldevice for measuring volumes, auxiliary devices may be present, such asa sensor for detecting the presence of an item on the conveyor belt,suitable for emitting a signal to actuate the optical readingapparatuses and the other components; a device for measuring the speedof the conveyor belt as a parameter to be taken into account in theprocessing of the photosensitive element output signal; devices formeasuring the height and/or position of the item on the conveyor belt,intended to provide useful indications for focusing the optical codeand, more in general, for performing a good reading.

The connection of each optical reading apparatus to the power supplyand/or to the other devices of the system where it is used, such as theabove auxiliary devices and/or the external processing unit, istypically realized via cable and preferably through removableconnectors, because of the complexity of the connections themselves,which often makes the use of a single cable impossible, and because manyconnections are standardized.

As an alternative or in addition thereto, in some applications there canbe provided a cordless interface through radio units and antennae orinfrared transceivers.

An automatic optical reading apparatus therefore generally comprises anoutside interface section.

In an optical reading apparatus, the emitting section and the receivingsection, which comprise fragile components, are especially subject towear and failures. In case of failure or breakage of a component of aknown optical reading apparatus, the entire apparatus must be replacedat least at the end user's level.

In fact, the integrity of the casing of known optical readingapparatuses, housing all the emitting, receiving and interface sections,as well as the above optional additional components, cannot be tamperedby the end user due to the safety regulations, in particular in the caseof laser light sources.

The replacement of the entire optical reading apparatus requires anin-depth knowledge of the entire system, since the substitute opticalreading apparatus and the components interacting with it must at leastbe connected again, resulting in a time-consuming and costly operation.

Known optical reading apparatuses are not only produced in a wide rangeof functional performances, but also in a range of layouts.

In particular, the exit of connection cables or connectors from thecasing of common optical reading apparatuses may be on a wall of thecasing of the optical reading apparatus, —generally known as “interfacewall”—, opposed to or adjoining a wall of the casing containing thelight emitting/receiving window. The antennae and transceivers providedfor cordless communication have a similar distribution on the casing ofthe optical reading apparatus.

The installation of a particular known automatic optical readingapparatus is sometimes difficult due to the restricted space available,which does not allow installing the apparatus with its wall containingthe emitting/receiving window facing the intended reading field due tothe space taken up by the connection cables at a predetermined wall ofthe apparatus casing. This applies to a greater extent in case ofinterface through connectors, that can take up a space even equal to30-40% of the overall size of the optical reading apparatus

Also in case of cordless communication, given the directionality oftypically used antennae and the need for conjugated transceivers to faceeach other, the predetermined mutual orientation of the wall containingthe emitting/receiving window and of the interface wall does not alwayscoincide with the optimum arrangement of the optical reading apparatusin the complex system where it is used.

In these cases, it is necessary to use a different optical readingapparatus, wherein the interface wall is arranged in a different mannerwith respect to the wall containing the emitting/receiving window, or touse light returning or deflecting mirrors. The first solution impliesthe need of producing—and thus assembling and stocking—optical readingapparatuses having identical or equivalent performance, differing in theoutside casing only.

The second solution implies even more considerable disadvantages. Infact, the installation of the optical reading apparatus together withthe necessary deflecting mirrors implies complex alignment procedures.

In known optical reading apparatuses, the control of the analoguecomponents of the emitting section and of the receiving section isperformed by an electronic controller, which however is in turncontrolled and programmed through algorithms residing in the singlemicroprocessor processing unit present, that is to say, the decoder inthe case of an optical code reader, or the processing unit intended todetermine distances and volumes in the case of measuring devices.

In optical reading apparatuses the need may arise of configuring someparameters of the apparatus internal components on the spot. Suchparameters comprise, among the others, the gain of signal amplifiers andpreamplifiers, the band-pass of the various electric and electroniccomponents, the switching thresholds applied in the digitalization ofthe output signal of the photosensitive element (or of such outputsignal after processing through the analogue-to-digital converter or thesampler), the scanning speed or speed profile of the light beam in thecase of a laser reader, for example the speed profile of a motor formoving a scanning mirror or mirror system, as well as some parameters ofthe treatment and/or processing algorithms of the output signal of thephotosensitive element.

As a general rule, the programming of such parameters, in particular ofanalogue component parameters, requires a fine tuning on the spot, andthus the presence of a high-level operator both during the firstinstallation of the optical reading apparatus and during replacementthereof, in case of failure or breakage of a component.

The complex systems wherein the optical reading apparatuses areinstalled are often provided with a certain redundancy, in particular,with a redundant number of optical code readers with at least partlysuperimposed reading areas to ensure good reading performances in caseof particularly damaged optical codes.

SUMMARY OF THE INVENTION

In the present description and attached claims, the expression “opticalreading apparatus” is used to indicate optical code readers, to whichreference shall be mainly made merely by way of an example, as well asdevices for measuring distances, devices for measuring volumes anddevices for detecting the presence of objects.

In the following description and claims, the expression “optical code”is used to indicate bar codes, “stacked” codes—that is, with morestacked bar sequences—, two-dimensional codes, color codes and the like.

In the present description and attached claims, the term “digitizer” isused to indicate a device suitable for receiving an input signal havingmore values, be it either a continuous analogue signal or a signalsampled over time and optionally quantized, for example a signal in thegrey scale, and for providing a two-level output signal, in particularrepresentative of the relative sizes of bars and spaces of a bar code,or more in general, of the presence and absence of the elements formingthe particular optical bar code being read.

In the present description and attached claims, the expression “outsideinterface section” is used to indicate the totality of bothphysical—such as cables and connectors—and cordless communicationdevices suitable for allowing the above interaction of the opticalreading apparatus with the system of which it is part, as well as theoptional interface electronics and the software controlling, forexample, the data communication protocol.

The technical problem at the basis of the present invention is that ofproviding an optical reading apparatus which should be of a simpler andmore versatile installation, maintenance and manufacture.

The invention relates to an automatic optical apparatus, comprising alight emitting section, a light receiving section and an outsideinterface section, characterized by comprising a first unit housing atleast one of the emitting section and the receiving section, and asecond unit housing at least the outside interface section, the firstunit and the second unit being mutually connectable.

The provision of a modular device allows minimizing the components to bereplaced in case of failure. Moreover, in case of failure of the firstunit, it is not necessary to disconnect and reconnect any connectioncables of the outside interface section.

Moreover, the provision of a modular device allows simplifyingproduction and reducing supply on hand, since a single first or,respectively, second unit can be produced for coupling to second or,respectively, first units, differing in function and/or layout.Moreover, the provision of a modular device allows selecting amongdifferent units during installation, based on factors external to theoptical reading apparatus, for example it allows selecting units of adifferent layout based on space factors.

In an embodiment, the first unit houses both the emitting section andthe receiving section, thus acting as a reading head.

In an embodiment of the present invention, the first unit has a firstcasing and the second unit has a second casing, the first and the secondcasing exhibiting conjugated removable fixing means suitable forallowing a mutual connection of the first and of the second casing in atleast two different mutual orientations.

Such a provision exhibits the advantage of making it possible to decide,during installation, the optimum mutual orientation of the two unitsbased on the complex system wherein the optical reading apparatus is tobe installed, in particular based on space considerations. The aboveprovision obviates to such disadvantages of known optical readingapparatuses as described above.

Preferably, the first casing exhibits an emitting and/or receivingwindow arranged in an orthogonal wall with respect to a wall forcoupling with the second unit.

As an alternative, the first casing exhibits an emitting and/orreceiving window arranged in an opposed wall with respect to the wallfor coupling with the second unit.

In the first or in the second case, the second casing exhibits aninterface wall, preferably arranged orthogonally with respect to a wallfor coupling with the first unit.

As an alternative, the second casing exhibits an interface wall which isarranged opposed with respect to the wall for coupling with the firstunit.

Even though an embodiment wherein the emitting and/or receiving windowand the interface wall are both arranged in walls orthogonal to thecoupling walls is particularly advantageous, since it is then possibleto change the mutual orientation of the planes containing them, also theother possible combinations are practically advantageous.

In fact, the emitting and/or receiving window exhibits an intrinsicdirectionality due to the direction of the scanning line—even though itis sometimes insensitive to a 180° rotation, as in bidirectionalreaders—so that its orientation, even though in a determined plane withrespect to the interface wall, may be necessary. Similarly, since theinterface wall may exhibit a high number of connectors, its orientation,even though in a predetermined plane with respect to the wall containingthe emitting/receiving window, may turn out to be profitable to avoid orreduce crossing of the connection cables and the interposition ofconnection cables in the optimum emitting and receiving path of anantenna or an infrared interface transceiver.

Preferably, a coupling portion of the first unit and a coupling portionof the second unit exhibit a shape selected between rectangular,circular and of a regular polygon with a certain number of sides,preferably at least four.

A shape of the coupling portions as a regular polygon with n sidesallows n mutual orientations, a circular shape allows numberless mutualorientations, a rectangular shape allows two mutual orientations.

In the following description and attached claims, the expression“coupling portion” is used to indicate a portion of the coupling wall,the entire coupling wall or a flange extending at the coupling wall.Thus, the first and the second unit must not necessarily have the samesize and shape at the coupling wall, rather they can be for exampleessentially parallelepiped with a circular or hexagonal coupling flange.Also, they can have a parallelepiped shape, a first unit having a squarecoupling wall and the other unit having a rectangular coupling wall anda square coupling portion, etcetera.

Preferably, the first and/or the second casing comprise a recess at therespective coupling wall.

Such a recess allows housing the cables and buses interconnecting theunits.

More specifically, the first casing can exhibit a plurality of firstremovable fixing elements identical to one another and equallydistributed along the perimeter of a portion for coupling with thesecond casing, and the second casing can exhibit a plurality of secondremovable fixing elements identical to one another and equallydistributed along the perimeter of a portion for coupling with the firstcasing, the first fixing elements and the second fixing elements beingconjugated.

In the present description and attached claims, the expression“conjugated removable fixing elements” is used to indicate threadedholes and screws, nuts and bolts, tabs and respective seats, bayonetjoints, snap-wise coupling surfaces, and the like.

Moreover, in an embodiment, each unit comprises respectivemicroprocessor processing means suitable for controlling the componentsof the respective unit.

In this way, the advantages of the modularity of the optical readingapparatus according to the invention further increase since the firstand the second unit are capable of operating independently of oneanother.

Again for the purpose of further increasing the modularity of theoptical reading apparatus, the first and the second unit preferablycomprise means for storing the setting parameters of the respectivecomponents.

Even more preferably, in at least one of the first and the second unitmeans for controlling the transfer of the setting parameters between thestorage means of the first unit and the storage means of the second unitare provided.

Such a provision allows facilitating the setting of the variousparameters during installation and replacement of one of the two units.

The above provision obviates to the above described disadvantages ofknown optical reading apparatuses. In fact, during installation andthrough the parameter transfer control means, it is possible to initiatethe copy of the parameter values set in each unit into the other unit.In this way, the operation of replacement of a unit can be carried outby non-skilled personnel, since it is sufficient to initiate—againthrough the parameter transfer control means—the copy of the parametervalues set in the replaced unit from the non-replaced unit, withouthaving to set them again.

The parameter transfer control means preferably comprises a manualcontrol device of an automatic data download routine, such as forexample a simple multi-position switch.

Typically, the optical reading apparatus also comprises an amplifier forthe output signal of the photosensitive element of the receivingsection, housed in one of the first unit and the second unit, preferablyin the first unit.

Typically, the optical reading apparatus also comprises ananalogue-to-digital converter or a sampler of the output signal of thephotosensitive element of the receiving section, housed in one of thefirst unit and the second unit, preferably in the first unit.

Typically, the optical reading apparatus also comprises a digitizerhoused in one of the first unit and the second unit, preferably in thefirst unit.

Preferably, moreover, the second unit houses the high heat generationcomponents and the first unit houses the optical components.

In particular, by arranging the low heat generation components in thefirst unit and the decoder and/or the processing unit for determiningdistances and/or volume in the second unit, the casing of the first unitcan be made so as to ensure a high protection against water, dust, andimpurities, which might contaminate the optical parts of the emittingand/or receiving sections, typically according to the IP65 standard.

Preferably, the casing of the first unit is airtight.

More preferably, the casing of the first unit is made of a plasticmaterial.

As an alternative or in addition, the emitting section and the receivingsection are preferably housed in a unit other than the second unit, andthe second unit is provided with cooling means.

Since the second unit does not contain the optical components, it doesnot need a high degree of protection against impurities, and it can thusbe cooled in any manner, for example by providing its casing withopenings and/or cooling fins, and/or making it in a metal material.

Such an arrangement allows increasing the operating temperature of theoptical reading apparatus with respect to known devices, wherein allcomponents, both optical and with a high heat generation, such as theprocessing unit and a power supply, are housed within a common casing,which must thus exhibit a high degree of protection.

In the present description and attached claims, the term “power supply”is used to indicate a component suitable for receiving a first voltagein input, typically a low-voltage continuous voltage or the supply mainsvoltage, and providing in output one or more levels of voltage suitablefor feeding the optical, electromechanical and electronic components ofthe optical reading apparatus.

Typically, the interface section is suitable for connecting the opticalreading apparatus to the external world, for example through serialports, in a multidrop network, via communication bus with similaroptical reading apparatuses, etcetera.

By arranging the interface section in the second unit according to theinvention, there is the further advantage that, in case of failure orbreakage of one of the components of the first unit, the second unit cancontinue to operate momentarily—along with the complex system whereinthe optical reading apparatus is installed—until the first unit isreplaced, even though without reading capability. In other words, it isnot necessary to stop the overall system even if momentarily a singleoptical reading apparatus does not perform the reading, in particular,does not read optical codes.

As explained above, the complex systems wherein the optical readingapparatuses are installed are often provided with a certain redundancy,in particular, with a redundant number of optical code readers with atleast partly superimposed reading areas to ensure good readingperformances in case of particularly damaged optical codes. Themomentary inefficiency of an optical reading apparatus, in particular ofan optical code reader, may thus have no impact on the overall systemperformance when it is made according to the invention.

The interface section can comprise at least one cordless communicationdevice.

Preferably, moreover, the second unit further houses a power supply.

Preferably, the second unit further houses means for digitallyprocessing the signal detected by the receiving section.

In the case of an optical code reader, the digital processing meanscomprises means for decoding an optical code.

In the case of a device for measuring distances or volumes, the digitalprocessing means is intended to calculate the distance or volume.

In an embodiment, the first unit comprises the emitting section and theoptical reading apparatus comprises a third unit housing the receivingsection.

As an alternative or in addition, the optical reading apparatuscomprises at least one additional unit housing at least one of a furtheremitting section and a further receiving section.

In this way, the optical reading apparatus can tun out to be providedwith two (or more) “reading heads” sharing some components, inparticular the decoder or the processing unit intended to determinedistances or volume. The additional reading head can be a backup one or,for example, can perform a scanning line not coinciding with thescanning line of the main reading head.

The above also applies to each third unit and/or to any additional unit;in particular, such a unit will be connectable according to at least twodifferent orientations with respect to the first, the second and/or anyother additional unit, and it can be provided with its own processingmeans suitable for controlling its components, with its own means forstoring the parameters, and with its own means for controlling thesetting parameter transfer between itself and the other units.

In a particularly preferred embodiment, the first unit houses theemitting section and the receiving section and first processing means,and the second unit houses the outside interface section and secondprocessing means, the first unit and the second unit being mutuallyconnectable in at least two different mutual orientations.

More preferably, each of the first and the second unit comprises meansfor storing the setting parameters of the respective components.

Even more preferably, in at least one of the first and the second unitmeans for controlling the setting parameter transfer between the storagemeans of the first unit and the storage means of the second unit areprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will beillustrated with reference to embodiments represented by way of anon-limiting example in the attached drawings, wherein:

FIG. 1 shows a perspective view of a first embodiment of an opticalreading apparatus according to the present invention;

FIG. 2 shows a perspective view of the optical reading apparatus of FIG.1 in a second assembled configuration;

FIG. 3 schematically shows an optical reading apparatus according to thepresent invention in a non-assembled condition;

FIGS. 4 to 9 schematically show further embodiments of an opticalreading apparatus according to the invention;

FIG. 10 schematically shows the arrangement of the internal componentsof an embodiment of an optical reading apparatus according to thepresent invention;

FIG. 11 schematically shows an embodiment of an optical readingapparatus according to the invention comprising three units; and

FIG. 12 schematically shows another embodiment of an optical readingapparatus according to the invention comprising three units.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The entire content of European Application No. 01830631.6 filed Oct. 5,2001 and U.S. application Ser. No. 10/167,991 filed Jun. 10, 2002, nowU.S. Pat. No. 7,197,162 issued on Mar. 27, 2007, is hereby incorporatedby reference.

With reference to the figures an optical reading apparatus 1 accordingto the present invention comprises a first unit 2 and a second unit 3.

The first unit 2 has an outer casing provided with a lightemitting/receiving window 22 on a wall 23.

The casing 21 is made, for example, of a plastic material and is freefrom openings.

The second unit 3 has an outer casing 31 provided with an input/output(I/O) panel 32 on an outside interface wall 33 or, briefly, I/O wall.The I/O panel 32 is shown as comprising a plurality of connectors 321,but this should be construed as purely illustrative. More generally,data communication cables, connectors and/or antennae, as well as asupply cable or a connector for a supply cable will be comprised.

The casing 31 is, for example, made of a metallic material and isprovided with openings and/or cooling fans 311.

The first unit 2 and the second unit 3 are mutually connectable at arespective coupling portion, 24 and 34, of a respective coupling wall,25 and 35.

According to an advantageous aspect of the present invention, in FIGS. 1and 2 the coupling portions 24, 34 have a square shape and coincide withthe coupling walls 25, 35, More specifically, the first and the secondunit 2, 3 are coupled through four screw and threaded hole couplings251, at the four vertices of the coupling portions 24, 34.

The square shape of the coupling portions 24, 34 allows the first unit 2and the second unit 3 to be connectable in four different mutualorientations.

Thus, in the arrangement of FIG. 1, indicating as the front wall of theapparatus 1 the one containing the emitting/receiving window 22 of thefirst unit 2, the I/O wall 33 of the second unit 3, containing the I/Opanel 32, is arranged in a left-hand side wall of the apparatus 1.

It is worth highlighting that the terms “front”, “left-hand side” andsimilar are used for ease of description, thus establishing a referencewhich must only be construed as being relative. Indeed, in theinstallation of the optical reading apparatus 1, it can take up anyabsolute orientation so that the emitting/receiving window 22 isarranged in the desired manner with respect to the intended readingzone.

In the arrangement of FIG. 2, again indicating as the front wall of theapparatus 1 the one containing the emitting/receiving window 22, the I/Owall 33 of the second unit 3, containing the I/O panel 32, is arrangedin a rear wall of the apparatus 1.

In the two remaining arrangements (not shown), the I/O wall 33 of thesecond unit 3, containing the I/O panel 32, is arranged in the samefront wall of the apparatus 1 or in a right-hand side wall thereof.

The relative orientation of the two units 2, 3 and in practice therelative orientation of the emitting/receiving window 22 and of the I/Owall 33 can therefore be chosen during installation, given theorientation of the emitting/receiving window 22 with respect to thereading zone, according to the preferred exit side of the connectioncables, having considered the available space and in view of theconnection to the remaining devices and apparatuses of the complexsystem in which the optical reading apparatus 1 is installed, or in viewof the location of a remote antenna or transceiver device, connected toan antenna or transceiver device for cordless communication of theoptical reading apparatus 1.

In FIG. 3 interconnection cables 252 are visible exiting from thecoupling wall 25 of the first unit 2 and relative interconnectionconnectors 351 arranged in a recess 352 of the coupling wall 35 of thesecond unit 3. The interconnection cables 252, when the optical readingapparatus 1 is assembled, are housed in the recess 352.

FIG. 3 differs from FIGS. 1 and 2 in that the coupling portion 24 of thefirst unit 2 is formed in a rectangular coupling wall 25.

In the embodiment of FIG. 4, the casings 21 and 22 of the first and thesecond unit 2, 3 are cylindrical and can be coupled at circular couplingportions 24, 34 (coupling walls 25, 35). The mutual orientation of thetwo units 2, 3 can therefore be varied as desired.

In the embodiment of FIG. 5, the casings 21 and 22 of the first and ofthe second unit 2, 3 are parallelepiped with a hexagonal base, allowingsix different mutual orientations of the two units 2, 3.

In FIGS. 1 to 5, the wall 23 containing the emitting window 22 of thefirst unit 2 is orthogonal to the coupling wall 25 of the first unit 2and the I/O wall 33 containing the I/O panel 32 of the second unit 3 isorthogonal to the coupling wall 35 of the second unit 3. Moreover, theemitting window 22 has its own longer side (i.e., the direction of thescanning line) parallel to the coupling wall 25.

Although such an arrangement is preferred, in alternative embodimentsthe emitting window 22 can have its own longer side (i.e. the directionof the scanning line) orthogonal to the coupling wall 25 (FIG. 6),and/or the wall 23 containing the emitting window 22 can be parallel andopposite to the coupling wall 25 of the first unit 2 (FIGS. 7 and 8),and/or the I/O wall 33 can be parallel and opposite to the coupling wall35 of the second unit 3 (FIGS. 8 and 9).

With reference now to FIG. 10, the first unit 2 houses a light emittingsection 26.

The light emitting section 26 comprises a laser light source 261 and apolygonal mirror 262, caused to rotate by a motor 263. In the path ofthe laser light beam L between the laser light source 261 and thepolygonal mirror 262 a flat mirror 264 is also interposed. The flatmirror 264 is sloped with respect to the direction of the laser lightbeam L and is equipped with a hole 265 for passage thereof.

The first unit 2 further houses a light receiving section 27.

The light receiving section 27 comprises, besides the polygonal mirror262 and the flat mirror 264, an optical focussing element 271, forexample a lens or a lens system, as well as a photosensitive element 272with a respective amplifier 273.

The first unit 2 further comprises a digitizer 28 which, as an input,receives the output signal of the photosensitive element 272, amplifiedby the amplifier 273, and provides a two-level output signal.

The first unit 2 finally comprises a microprocessor processing unit orcontroller 29 for controlling the motor 263, the photosensitive element272 and amplifier 273, the light source 261 and/or the digitizer 28.

Accordingly, the first unit 2 can function independently from the secondunit 3.

The controller 29 comprises, according to an advantageous aspect of thepresent invention, storing means 291, suitable for containing the setvalues of the parameters relative to the components not just of thefirst unit 2, but also of the second unit 3. In case of replacement ofthe second unit 3, the values of the setting parameters of a new secondunit 3 can therefore be copied from the storing means 291, without theneed to carry out the calibration procedures once again.

The second unit 3 comprises an outside interface section 36, illustratedas comprising a supply cable 361 and a data input/output (I/O) module362. Such a data input/output module can, for example, comprise one ormore cables, in particular communication buses or cables for connectionin a serial network or in a multidrop network, one or more radiomodules, one or more transceivers, an interface electronics and/orsoftware programs controlling, for example, the data communicationprotocol.

The second unit 3 further comprises a microprocessor processing unit 37,intended to decode the read optical code or to determine distances orvolume, which allows the operation of the second unit 3 independentlyfrom the first unit 2.

The microprocessor processing unit 37, moreover, is intended to programthe setting parameters of the controller 29 of the components of thefirst unit 2, such as, for example, the gain and the pass-band of thephotosensitive element 272 and of the amplifier 273, the switchingthresholds of the digitizer 28, the speed or the speed profile of themotor 263, besides to program some parameters of the signal processingalgorithms implemented in the unit itself.

According to an advantageous aspect of the present invention, themicroprocessor processing unit 37 comprises storing means 371 capable ofcontaining the set values of parameters relative to the components notjust of the second unit 3, but also of the first unit 2. In case ofreplacement of the first unit 2, such set values can be downloaded intothe storing means 291 of the first unit 2, without the need to carry outthe calibration procedures once again.

A manual control device, such as a multi-position switch 372 in thesecond unit 3, allows the initiation of an automatic download routine ofthe values of the parameters between the second unit 3 and the firstunit 2.

The second unit 3, finally, comprises a power supply 38 for thedistribution of the power received from the cable 361 to the variouscomponents of the first unit 2 and of the second unit 3.

FIG. 11 schematically shows an optical reading apparatus 1 according tothe present invention wherein the first unit 2 houses the emittingsection 26 (not shown) in a casing 21 equipped with an emitting window22, and, besides the second unit 3 housing the outside interface section36 (not shown), a third unit 4 is also present.

The third unit 4 houses the receiving section 27 (not shown) and has athird casing 41 provided with a receiving window 42. Of course, theemitting section and the receiving section are of a type not comprisingcommon optical components.

The third casing 41 and the first casing 21, as well as the third casing41 and the second casing 31, are coupled through conjugated removablefixing means (not shown) at respective coupling portions 24, 34, 44 a,44 b of such a shape as to allow at least two different mutualorientations between the third casing 41 and the second casing 31 and/orthe first casing 21, having a rectangular shape in FIG. 11.

FIG. 12 schematically shows an optical reading apparatus 1 according tothe present invention wherein the first unit 2 houses the emittingsection 26 and the receiving section 27 (both not shown) in a casing 21provided with an emitting/receiving window 22, and, besides the secondunit 3 housing the outside interface section 36 (not shown), a fourthunit 5 is also present.

The fourth unit 5 houses a further emitting section and a furtherreceiving section (both not shown) and has a fourth casing 51 providedwith an emitting/receiving window 52.

The fourth casing 51 and the first casing 21, as well as the fourthcasing 51 and the second casing 31, are coupled through conjugatedremovable fixing means (not shown) at respective coupling portions 24,34, 54 a, 54 b having a shape such as to allow at least two differentmutual orientations between the fourth casing 51 and the second casing31 and/or the first casing 21, having a square shape in FIG. 11.

It is manifest that other changes, variants, replacements and additionscan be made to the previously described embodiments without thusdeparting from the scope of the present invention.

As an alternative to the single emitting/receiving window 22, the casing21 of the first unit 2, as well as the casing 51 of the additional unit5 of FIG. 12, can comprise distinct emitting and receiving windows.

The screws and threaded holes 251 are merely illustrative of removablefixing means for the connection of the two units 2, 3. Other removablefixing means can comprise nuts and bolts, tabs and relative seats,bayonet couplings, snap-wise coupling surfaces, etc.

For housing the interconnection cables 252, as an alternative or inaddition to the recess 352 of the coupling wall 35 of the second unit 3,there can be a recess at the coupling wall 25 of the first unit 2.

The coupling portions 24, 34 and/or the coupling walls 25, 35 can haveshapes other than those described. For example, they can have asubstantially horseshoe form, which however allows just one mutualorientation, a rectangular or elliptical shape, which allows just twomutual orientations or else a regular polygonal shape, which allows anumber of mutual orientations equal to the number of sides thereof.

Also as far as FIGS. 4, 5, 11 and 12 are concerned, the shape of thecasings 21 and 31 of the first and of the second unit 2, 3 is notrelated to the shape of the coupling portions 24, 34, rather they can beof whatever shape, even a different one for the various units 2, 3, 4,5. Thus, the coupling portions 24, 34 which are circular, polygonal,rectangular and square, respectively, can be formed as part of thecoupling walls 25, 35 or else as flanges extended at the coupling walls25, 35.

Though illustrated in FIGS. 6-9 with reference to square couplingportions 24, 25, the alternative arrangements of the emitting window 22and of the I/O wall 33 with respect to the coupling walls 25, 35 applywith all of the possible shapes of the coupling portions 24, 34 and alsoin the presence of the third unit 4 and of one or more additional units5, of course excluding in such a case their arrangement at the couplingwalls between adjacent units.

In the embodiments of FIGS. 11 and 12, the mutual arrangement of thevarious units 2, 3, 4 and 2, 3, 5 can be changed as desired.

Also the components of the emitting section 26 and of the receivingsection 27 illustrated and described are merely examples and can bereplaced by other components suitable for carrying out the samefunctions.

Thus, for example, in the emitting section 26, the flat mirror 264provided with the hole 265 can be missing, just as optical elements forfocussing and shaping the laser light beam L can be included.

Moreover, the emitting section 26 can comprise scanning means other thanthe polygonal mirror 262. For example, an oscillating mirror or else adevice for moving the laser light source 261 can be provided.

Also, the emitting section 26 can be of the type comprising aone-dimensional or two-dimensional array of light sources, for exampleof light emitting diodes (LEDs).

In the receiving section 27, the polygonal mirror 262 and the flatmirror 264 can be missing or replaced by different light-collectingoptical elements.

The photosensitive element 272 can consist of a single photodiode, of aone-dimensional or two-dimensional array of photodiodes, of a linear orarray CCD or C-MOS device.

Although they are illustrated as a single component, the photosensitiveelement 272 and the amplifier 273 can be separate components, eachindependently controlled by the controller 29 and fed by the powersupply 38. The amplifier 273 can, moreover, be housed in the second unit2 or even be missing.

In case of embodiments wherein the components of the light emittingsection 26 and of the light receiving section 27 are totally separated,one or the other can be housed in the second unit 3 instead of in thefirst unit 2, as well as in a third unit 4.

The processing of the digital signal, in particular the decoding of anoptical code or the determination of the measures or of the volume, cantake place outside of the optical reading apparatus 1, in which case themicroprocessor processing unit indicated as decoder 37 can be completelymissing or can only be intended to store the setting parameters of thecomponents of the first unit 2 or can be limited to the storing of theparameters of the microprocessor processing unit 29 of the first unit(if present); in such a case the outside interface section 36 shall bemade up of a simple cable or cable connector for the communication ofthe output signal of the photosensitive element 272.

As an alternative to just the digitizer 28 housed in the first unit 2,for the treatment of the output signal of the photosensitive element272, different components, such as an amplifier and ananalogue-to-digital converter or a sampler, followed by a digitizer canbe provided. Such components can be distributed between the first unit 2and the second unit 3. Still as an alternative, some or all of suchcomponents can be external to the optical reading apparatus 1.

In the case of an optical reading apparatus 1 operating on signals atmany levels, for example in the case of a color optical code reader, thedigitizer 28 can be completely missing or replaced by ananalogue-to-digital converter or by a sampler.

The memory 291 and the memory 371 can alternatively be external to thecontroller 29 and the decoder 37, respectively.

The manual control device 372 for downloading the values of theparameters can alternatively be arranged in the first unit 2.

As an alternative or in addition to the openings and/or cooling fins311, the second unit 3 can comprise further cooling means, for example afan.

The power supply 38 could alternatively be housed in the first unit 2.Still as an alternative, two (or more) power supplies can be included,one in each unit 2, 3 (and 4, 5 if present).

Even more generally, to obtain reading redundancy, the number ofemitting sections and the number of receiving sections presentaltogether do not necessarily have to be the same, provided that suchsections can be activated upon command so as to effectively operate aspairs of an emitting section and a receiving section each.

The communication and the transfer of the parameters between the variousunits 2, 3, 4, 5 present can be mono-directional or bi-directional.

The above specification provides a complete description of theinvention. Since many embodiments of the invention can be made withoutdeparting from the spirit and scope of the invention, the inventionresides in the claims hereinafter appended.

1. Automatic optical reading apparatus, comprising: a light emittingsection; a light receiving section; an outside interface section; afirst unit housing at least one of the emitting section and thereceiving section; a second unit housing at least the outside interfacesection; the first unit and the second unit being mutually connectable;and the first and second unit each having respective microprocessorprocessing means for controlling the components of the respective unit.2. Automatic optical reading apparatus according to claim 21, whereineach of the first and the second units has storage means for storing thesetting parameters of the respective components.
 3. Automatic opticalreading apparatus according to claim 22, wherein at least one of thefirst and the second unit has means for controlling the settingparameter transfer between the storage means of the first unit and thestorage means of the second unit.
 4. Automatic optical reading apparatusaccording to claim 23, wherein the parameter transfer control meanscomprise a manual control device of a download routine.
 5. Automaticoptical reading apparatus according to claim 21, further comprising anamplifier of the output signal of a photosensitive element of thereceiving section, housed in the first unit.
 6. Automatic opticalreading apparatus according to claim 21, further comprising ananalogue-to-digital converter or a sampler of the output signal of aphotosensitive element of the receiving section, housed in the firstunit.
 7. Automatic optical reading apparatus according to claim 21,further comprising a digitizer housed in the first unit.
 8. Automaticoptical reading apparatus according to claim 21, wherein the second unitfurther houses digital processing means of an output signal of thereceiving section.
 9. Automatic optical reading apparatus according toclaim 28, wherein the digital processing means comprises means fordecoding an optical code.
 10. Automatic optical reading apparatusaccording to claim 21, wherein the first unit houses both the emittingsection and the receiving section.